【正文】 c Potassium Phosphate Magnesium Sulfate (MgSO4. –Johnson Agar Medium Pancreatic Digest of Casein Yeast Extract Mannitol Dibasic Potassium Phosphate Lithium Chloride Glycine Agar Phenol Red Water 1000mL Boil the solution of solids for ,cool to between 45 and 50 ,and add 20mLof sterile potassium tellurite solution (1in 100). pHafter sterilization:177。. Soybean–Casein Digest Medium Prepare as directed for Soybean–Casein Digest Mediumunder Sterility Tests ?71?. –Salt Agar Medium Pancreatic Digest of Casein Peptic Digest of Animal Tissue Beef Extract DMannitol Sodium Chloride Agar Phenol Red Water 1000mL Mix,then heat with frequent agitation, and boil for 1minute to effect solution. pHafter sterilization:177。2 . Where agar is called for in a formula, use agar that has a moisture content of not more than 15%.Where water is called for in a formula, use Purified Water. Buffer Stock Solution— Dissolve 34g of monobasic potassium phosphate in about 500mLof water contained in a 1000mLvolumetric flask. Adjust to 177。?61?MICROBIAL LIMIT TESTS This chapter provides tests for the estimation of the number of viable aerobic microanisms present and for freedom from designated microbial species in pharmaceutical articles of all kinds, from raw materials to the finished forms. An automated method may be substituted for the tests presented here, provided it has been properly validated as giving equivalent or better results. In preparing for and in applying the tests, observe aseptic precautions in handling the specimens. Unless otherwise directed, where the procedure specifies simply ―incubate,‖ hold the container in air that is thermostatically controlled at a temperature between 30 and 35 ,for a period of 24to term ―growth‖ is used in a special sense herein, ., to designate the presence and presumed proliferation of viable microanisms. PREPARATORY TESTING The validity of the results of the tests set forth in this chapter rests largely upon the adequacy of a demonstration that the test specimens to which they are applied do not, of themselves, inhibit the multiplication, under the test conditions, of microanisms that may be present. Therefore, preparatory to conducting the tests on a regular basis and as circumstances require subsequently, inoculate diluted specimens of the material to be tested with separate viable cultures of Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Salmonella. This can be done by adding 1mLof not less than 10?3dilution of a 24hour broth culture of the microanism to the first dilution (in Buffer, Fluid Soybean–Casein Digest Medium, or Fluid Lactose Medium)of the test material and following the test procedure. Failure of the anism(s)to grow in the relevant medium invalidates that portion of the examination and necessitates a modification of the procedure by (1)an increase in the volume of diluent, the quantity of test material remaining the same, or by (2)the incorporation of a sufficient quantity of suitable inactivating agent(s)in the diluents, or by (3)an appropriate bination of modifications (1)and (2)so as to permit growth of the inocula. The following are examples of ingredients and their concentrations that may be added to the culture medium to neutralize inhibitory substances present in the sample: soy lecithin,%。and polysorbate 20,%. Alternatively, repeat the test as described in the preceding paragraph, using Fluid Casein Digest–Soy Lecithin–Polysorbate 20 Mediumto demonstrate neutralization of preservatives or other antimicrobial agents in the test material. Where inhibitory substances are contained in the product and the latter is soluble, a suitable, validated adaptation of a procedure set forth in the section Membrane Filtration under Test for Sterility of the Product to be Examinedunder Sterility Tests ?71?,may be used. If in spite of the incorporation of suitable inactivating agents and a substantial increase in the volume of diluent, it is still not possible to recover the viable cultures described above and where the article is not suitable for employment of membrane filtration, it can be assumed that the failure to isolate the inoculated anism is attributable to the bactericidal activity of the product. This information serves to indicate that the article is not likely to be contaminated with the given species of microanism. Monitoring should be continued in order to establish the spectrum of inhibition and bactericidal activity of the article. BUFFER SOLUTION AND MEDIA Culture media may be prepared as follows, or dehydrated culture media may be used provided that, when reconstituted as directed by the manufacturer or distributor, they have similar ingredients and/or yield media parable to those obtained from the formulas given herein. In preparing media by the formulas set forth herein, dissolve the soluble solids in the water, using heat, if necessary, to effect plete solution, and add solutions of hydrochloric acid or sodium hydroxide in quantities sufficient to yield the desired pH in the medium when it is ready for use. Determine the pH at 25177。 the addition of sodium hydroxide TS(about 175mL),add water to volume, and mix. Dispense and sterilize. Store under refrigeration. For use, dilute the Stock Solution with water in the ratio of 1to 800,and sterilize. Media Unless otherwise indicated, the media should be sterilized by heating in an autoclave (see Steam Sterilizationunder Sterilization ?1211?),the exposure time depending on the volume to be sterilized. Casein Digest–Soy Lecithin–Polysorbate 20Medium Pancreatic Digest of Casein 20g Soy Lecithin 5g Polysorbate 20 40mL Water 960mL Dissolve the pancreatic digest of casein and soy lecithin in 960mLof water, heating in a water bath at 48 to 50 for about 30minutes